Total mesorectal excision surgical simulator

ABSTRACT

A TME surgical simulator is provided. The TME surgical simulator includes a simulated tissue layers and simulated vasculature and/or organ structures. The simulated tissue surgical simulator is adapted for but not limited to laparoscopic and/or transanal TME surgical procedures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional patentapplication No. 62/607,476, filed on Dec. 19, 2017, the entiredisclosure of which is hereby incorporated by reference as if set infull herein.

BACKGROUND

This application is generally related to surgical training systems andmethods, and, in particular to, simulated tissue structures and modelsfor teaching, practicing and evaluating various surgical techniques andprocedures related to but not limited to total mesorectal excisionprocedures and techniques.

Medical students as well as experienced doctors learning new surgicaltechniques must undergo extensive training before, they are qualified toperform surgery on human patients. The training must teach propertechniques employing various medical devices for cutting, penetrating,clamping, grasping, stapling, cauterizing and suturing a variety oftissue types. The range of possibilities that a trainee may encounter isgreat. For example, different organs and patient anatomies and diseasesare presented. The thickness and consistency of the various tissuelayers will also vary from one part of the body to the next and from onepatient to another. Different procedures demand different skills.Furthermore, the trainee must practice techniques in various anatomicalenvirons that are influenced by factors such as the size and conditionof the patient, the adjacent anatomical landscape and the types oftargeted tissues and whether they are readily accessible or relativelyinaccessible.

Various teaching aids, trainers, simulators and model organs areavailable for one or more aspects of surgical training. However, thereis a need for models or simulated tissue elements that are likely to beencountered in and that can be used for practicing endoscopic andlaparoscopic, minimally invasive, transluminal surgical procedures. Inlaparoscopic surgery, a trocar or cannula is inserted to access a bodycavity and to create a channel for the insertion of a camera such as alaparoscope. The camera provides a live video feed capturing images thatare then displayed to the surgeon on one or more monitors. At least oneadditional small incision is made through which another trocar/cannulais inserted to create a pathway through which surgical instruments canbe passed for performing procedures observed on the monitor. Thetargeted tissue location such as the abdomen is typically enlarged bydelivering carbon dioxide gas to insufflate the body cavity and create aworking space large enough to accommodate the scope and instruments usedby the surgeon. The insufflation pressure in the tissue cavity ismaintained by using specialized trocars. Laparoscopic surgery offersseveral advantages when compared with an open procedure but requires anincreased level of skill as the target tissue is not directly observedby the clinician. The target tissue is observed on monitors displaying aportion of the surgical site that is accessed through a small opening.Therefore, clinicians need to practice visually determining tissueplanes, three-dimensional depth perception on a two-dimensional viewingscreen, hand-to-hand transfer of instruments, suturing, precisioncutting and tissue and instrument manipulation. Typically

One procedure is a total mesorectal excision (TME) for the treatment oflate stage colorectal cancer in which the entire mesorectal envelope anda portion of the rectum are removed. This procedure has shown reducedlocal recurrence rates and improved oncologic outcomes for patients. TheTME procedure can be performed using a combination of minimally invasivetechniques, including laparoscopic and transanal approaches. Currently,there is an unmet need of educational tools for surgeons to utilizewhile developing and practicing skills relevant to the TME procedure.

SUMMARY

In accordance with various embodiments of the present invention, a TMEsurgical simulator is provided. The surgical simulator comprises a framehaving a proximal opening and a distal opening and a simulated tissuelayer connected and covering the proximal opening. In variousembodiments, the surgical simulator further comprises a simulated organassembly extending through the distal opening.

In various embodiments, a surgical simulator comprises a frame having aproximal portion defining a simulated abdominal cavity and a distalportion defining a simulated pelvic cavity and a simulated parietalperitoneum layer connected to the proximal portion. In variousembodiments, the surgical simulator further comprises a simulated aortadisposed within the simulated abdominal cavity and a simulated prostatedisposed within the simulated pelvic cavity.

In various embodiments, a surgical simulator comprises a simulatedparietal peritoneum layer and a simulated mesorectum and mesentery layerconnected to the simulated parietal peritoneum layer and togetherforming a envelope there between. In various embodiments, the surgicalsimulator further comprises a simulated fatty fill disposed within theenvelope.

In various embodiments, a surgical simulator comprises a frame having aproximal portion defining a simulated abdominal cavity and a distalportion defining a simulated pelvic cavity, a simulated endopelvicfascia layer disposed within the simulated pelvic cavity and a simulatedpelvic floor layer attached to the simulated endopelvic fascia layer andthe distal portion of the frame. In various embodiments, the surgicalsimulator further comprises a simulated mesorectum layer attached to thesimulated endopelvic fascia layer, the simulated mesorectum layer andthe simulated endopelvic fascia layer defining a simulated dissectionplane therebetween.

In various embodiments, a surgical simulator comprises a frame having aproximal portion defining a simulated abdominal cavity and a distalportion defining a simulated pelvic cavity, a simulated visceralperitoneum layer disposed within the simulated abdominal cavity and asimulated peritoneum or parietal peritoneum attached to the simulatedvisceral peritoneum layer and the proximal portion of the frame. Invarious embodiments, the surgical simulator further comprises asimulated mesentery layer attached to the simulated Toldt's/endopelvicfascia layer, the simulated mesentery layer and the simulatedToldt's/endopelvic fascia layer defining a simulated dissection planethere between.

Many of the attendant features of the present invention will be morereadily appreciated as the same becomes better understood by referenceto the foregoing and following description and considered in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventions may be understood by reference to the followingdescription, taken in connection with the accompanying drawings in whichthe reference numerals designate like parts throughout the figuresthereof.

FIG. 1 is perspective view of a surgical simulator or model inaccordance with various embodiments of the present invention.

FIG. 2 is a side view of a surgical simulator in accordance with variousembodiments of the present invention.

FIG. 3 is a top view of a surgical simulator in accordance with variousembodiments of the present invention.

FIGS. 4A-4B are front cross-sectional semi-schematic diagrams of asurgical simulator in accordance with various embodiments of the presentinvention taken along the line A-A.

FIG. 5A is a perspective view of portions of a surgical simulator inaccordance with various embodiments of the present invention.

FIG. 5B is an exploded view of portions of a surgical simulator inaccordance with various embodiments of the present invention.

FIG. 6 is a perspective view of portions of a surgical simulator inaccordance with various embodiments of the present invention.

FIG. 7 is a side view of a surgical simulator in accordance with variousembodiments of the present invention.

FIGS. 8A-8B are front cross-sectional semi-schematic diagrams of asurgical simulator in accordance with various embodiments of the presentinvention taken along the line B-B.

FIG. 9 is a top view of a surgical simulator in accordance with variousembodiments of the present invention.

FIGS. 10A-10B are side cross-sectional semi-schematic diagrams of asurgical simulator in accordance with various embodiments of the presentinvention taken along the curved line C-C.

FIGS. 11A-11B are front cross-sectional semi-schematic diagrams ofvarious configurations of a surgical simulator in accordance withvarious embodiments of the present invention.

FIGS. 12A-12B are front cross-sectional semi-schematic diagrams ofvarious configurations of a surgical simulator in accordance withvarious embodiments of the present invention.

FIG. 13 is a front cross-sectional semi-schematic diagram of aconfiguration of a surgical simulator in accordance with variousembodiments of the present invention.

FIG. 14 is a perspective view of a frame of a surgical simulator inaccordance with various embodiments of the present invention.

FIG. 15 is a front view of a frame of a surgical simulator in accordancewith various embodiments of the present invention.

FIG. 16 is a perspective cross-sectional view of a frame of a surgicalsimulator in accordance with various embodiments of the presentinvention.

FIG. 17 is a top view of a frame of a surgical simulator in accordancewith various embodiments of the present invention.

FIG. 18 is a perspective view of a frame of a surgical simulator inaccordance with various embodiments of the present invention.

FIG. 19 is a perspective cross-sectional view of a frame of a surgicalsimulator in accordance with various embodiments of the presentinvention.

FIG. 20 is a side view of a frame of a surgical simulator in accordancewith various embodiments of the present invention.

DETAILED DESCRIPTION

Generally, a TME surgical simulator or model is provided to assist insurgical skill training and simulation. The TME simulator comprisesvarious simulated organ and/or tissue structure assemblies attached toeach other and positioned within a rigid frame. The simulated organstructure assemblies provide different simulated tissue planes and inparticular, distinguishable simulated dissection planes. Variousfeatures of the assemblies further provide added tactile and/or visualfeedback along with difficulties and challenges to simulate and furtherassist in training and assessment of a simulated TME surgical procedure.For example, varying sizes and/or attachment of various simulated organstructures and/or varying various compositions and/or toughness of suchstructures and assemblies are provided.

During a TME procedure, the fatty mesorectal envelope circumferencingthe rectum is removed along with a portion of the rectum. This procedurerequires ligation of the relevant blood supply as well ascircumferential mobilization of the rectum and mesorectum from thepelvic cavity and surrounding structures. Once the mesorectal specimenis removed, the mesorectum is inspected and graded; ranging fromincomplete to complete dissection of this tissue. This is determined byvisibility of the rectal lumen where segments of the mesorectum havebeen dissected into erroneously. Grading of the excised specimen can beused to assess surgical performance as well as local recurrence risk.

A TME procedure, as such, requires a high level of technical skill andunderstanding of the pelvic anatomy. The TME surgical simulator invarious embodiments mimics a portion of the pelvic anatomy and thus canmeet the clinical need in providing learning tools for surgeons to useduring their education. The TME surgical simulator in accordance withvarious embodiments allows for the execution and/or completion of asimulated TME procedure from a laparoscopic and/or transanal approach.In accordance with various embodiments, for compatibility with bothapproaches and realistic identification of the relevant anatomicallandmarks, the TME surgical simulator comprises at least one or more ofthe following simulated organ structures, tissue, vasculature and/ormaterials: colon, mesentery, mesorectum, Toldt's fascia, visceralperitoneum (retroperitoneum), endopelvic fascia, prostate, ureter,gonadal vessels, seminal vesicles, muscle layers, pelvic floor, IMA, IMVand aorta. The simulated materials, tissue layers and/or organstructures, in various embodiments, are also assembled in such a waythat allows the end user, e.g., the surgeon, to perform the simulatedprocedure such that it provides realistic tactile feedback similar tothat which one would encounter during the non-simulated procedure. This,among other things, allows the user to train on technical skilldevelopment associated with the identification of relevant anatomy andtissue handling. In accordance with various embodiments, the simulatedmaterials can be confined within a simulated pelvis, which providesrealistic limitations of the pelvic workspace including, for example,limited visualization occurring during dissection down the curved pelvicfloor during a TME procedure. The simulated materials in variousembodiments allows for the removal of the simulated mesorectum specimenwhich upon removal can be graded, for example, on a scale of 1-3 rangingfrom incomplete to complete dissection.

The TME surgical simulator according to various embodiments of thepresent invention is used to simulate a total mesorectal excisionprocedure. To provide a realistic procedural training environment, theTME surgical simulator or model provides laparoscopic and transanalaccess for the surgical procedure simulation. The surgical simulatorprovides simulated materials to represent the various anatomicallandmarks and planes, as well as materials to simulate dissection, whichprovides notable visual and tactile feedback useful to understand theanatomy and tissue handling in order to better understand thecomplications that can be encountered during a surgical procedure.Additionally, the TME surgical simulator provides materials to simulatethe mesorectum that allow the mesorectum to be mobilized, removed, andgraded. Portions of the simulator, such as the mesorectum, are providedsuch that it is sufficiently fragile and thus able to be damaged duringthe simulated procedure. This in turn allows the simulated mesorectumand the like to be assessed and/or graded similar to a surgicalprocedure. In various embodiments, the confinement of portions of thesurgical simulator in a simulated pelvis presents the realisticchallenge of working within a confined space. Additionally, in variousembodiments, the simulated pelvis has a curve integrated within itsshape to simulate the curve of the sacrum, which presents avisualization challenge during the surgical procedure. The TME surgicalsimulator in various embodiments can be used within a laparoscopictrainer and with laparoscopic instruments for a simulated procedure. TheTME surgical simulator, in accordance with various embodiments, relevantand realistic anatomy for the performance of each surgical step of theTME procedure.

Referring to FIGS. 1-3 and 14-20, the TME surgical simulator 10comprises a simulated pelvic frame or base 20. The frame 20 in variousembodiments is the hardest or most rigid portion of the simulator 10.The frame provides a platform raising and/or suspending simulated organor tissue structures 100 secured to the frame. The frame has a proximalend and a distal end in which the proximal end has enlarged opening 21relative to a restricted opening 22 at its distal end. In variousembodiments, the frame is sized and shaped to fit within the confines ofa laparoscopic trainer having specific and limited access points orchannels to access the TME surgical simulator and/or not air tight orable to seal in insufflation gas.

A proximal portion of the simulator 10 is a simulated abdominal cavityor portions thereof and a distal portion of the simulator is a simulatedpelvic cavity or portions thereof. As such, the proximal portion of theframe is set higher or above the distal portion of the frame. Similarly,simulated organ and/or tissue structures in the proximal portion aredifferent from those in the distal portion of the simulator 10. However,some common organ and/or tissue structures extend from the proximalportion to the distal portion. In the illustrated embodiment, at or nearthe proximal end of the frame extends a support or leg 23 and at or nearthe distal end of the frame extends a support or leg 24. The leg 23extends from a proximal portion of frame floor 25 and leg 24 extend froma distal portion of the frame floor 25 with the proximal portion of theframe floor being higher or positioned above the distal portion of theframe floor. The frame floor 25 extends into sidewalls 26 and at adistal portion extends to a roof or top 27. As such, in variousembodiments, the distal portion of the frame provides a confined curvedcavity or enclosure and at a distal end provides a generally circularopening and the proximal portion of the frame provides an enlargedcurved cavity with an enlarged opening. The frame floor 25 in variousembodiments starting at the proximal end of the frame extends laterally,curves down and back up at the distal end of the frame. In theillustrated embodiment, the legs and frame floor are integrated orformed as a single monolithic structure and in various embodiments areseparate components, connected together to form a simulated workingspace for the simulator 10. In various embodiments, the frame is formedplastic or a similar rigid material and in other various embodimentsincludes plastic sheets cut to shape and attached together, e.g., withmechanical fasteners, to form the frame. Various simulated organ andtissue structures, assemblies or subassemblies are secured and/orsupported by the frame.

Referring now also to FIGS. 4A-10B, the simulator 10 comprises asimulated pelvic floor assembly, a simulated Toldt's/endopelvic fasciaassembly, a colon/rectum assembly and a mesentery/mesorectum assembly.The simulated pelvic floor assembly comprises simulated Gonadal vessels32, simulated aorta 33 and simulated nerves 34 with a layer of fibrousmaterial, such as batting, attaching or otherwise placing the simulatedmaterial between or intermingling with the fibrous material and asimulated pelvic floor 31. In various embodiments, simulated pelvicfloor 31, simulated Gonadal vessels 32, simulated aorta 33 and simulatednerves 34 are all made of silicone but are colored or otherwisedistinguished from each other visually and/or tactilely. Similarly, thesimulated vessel structures have a different thickness or length tofurther distinguish the structures, such as the simulated aorta 33 beingthicker than the simulated nerves 34 and the simulated gonadal vessels32 and/or the simulated gonadal vessels being longer than the simulatednerves 34.

In accordance with various embodiments, the simulated Toldt's orendopelvic fascia assembly comprises a simulated Toldt's fascia/visceralperitoneum/endopelvic fascia sheet or layer 41 (“Toldt's/endopelvicfascia”) and simulated ureters 42 and in various embodiments simulatedblood vessels attached to the simulated ureters. The simulatedToldt's/endopelvic fascia sheet in various embodiments is made fromsilicone and fibrous material, e.g., batting, attached or cured thereto.The simulated ureters and associated vessels are also made of siliconeand are attached to the simulated Toldt's/endopelvic fascia sheet and invarious embodiments adhered or attached to a proximal portion of thesheet and/or on a smooth or non-fibrous side of the sheet. In variousembodiments, simulated ureters, vessels and Toldt's/endopelvic fasciasheet are colored or otherwise distinguished from each other visually,e.g., colored, and/or tactilely, e.g., having different dimensions,thickness and/or length.

In the illustrated embodiment, the simulated Gonadal vessels 32,simulated aorta 33 and simulated nerves 34 are adhered to the simulatedpelvic floor 31 which is attached to the frame and a distal portion ofthe simulated pelvic floor away from the simulated aorta 33 is cut,folded and shaped also attached to the frame. The simulated Gonadalvessels 32, simulated aorta 33 and/or simulated nerves 34 are also onlyaccessible and/or visible at or near the proximal portion of the TMEsurgical simulator while the simulated pelvic floor extends along orthroughout the entire length or interior of the frame. The simulatedureters 42 are also only accessible and/or visible at or near theproximal portion of the TME surgical simulator and thereby furthermimicking or closely representing portions of abdominal cavity in theTME surgical simulator. The Toldt's/endopelvic fascia sheet is adheredor otherwise attached to the pelvic floor placing the simulated uretersand vessel there between. Furthermore, a distal portion of theToldt's/endopelvic fascia sheet is shaped, formed and/or attached toitself to provide a generally enclosed or circular or oval enclosure atthe distal portion of the TME surgical simulator and thereby alsofurther mimicking or more closely representing portions of the pelviccavity in the TME surgical simulator.

In accordance with various embodiments, at a distal portion of the TMEsurgical simulator, a simulated prostate 43, simulated bladder 44 andsimulated seminal vesicles 45 are also provided and attached to thesimulated endopelvic sheet 41. As provided in the illustratedembodiment, the simulated bladder 44 is positioned above and somewhataround the simulated prostate 43 with the simulated prostate 43 having asimulated urethra 46 extending therefrom. The simulated seminal vesicles45 are positioned adjacent or next to the simulated prostate 43 and invarious embodiments, the simulated prostate 43, simulated bladder 44,simulated seminal vesicles 45 and/or simulated urethra 46 are disposedbetween the simulated pelvic floor 31 and the simulated endopelvicfascia sheet 41. In various embodiments, although not illustrated, theureters attach to the bladder towards the proximal end of the surgicalsimulator. In various embodiments, the simulated pelvic floor 31 coversthe simulated endopelvic fascia sheet 41 to form or define a cavity inwhich the simulated prostate 43, simulated bladder 44, simulated seminalvesicles 45 and/or simulated urethra 46 are captured or enclosedtherein. In accordance with various embodiments, the simulatedendopelvic fascia sheet 41 is adhered to the simulated pelvic floor 31,which is then placed under an outward tension or away from the interiorof the frame but still within the confines of frame. In variousembodiments, the simulated pelvic floor is stretched or pulled towardsthe interior of frame after being adhered to the frame to ultimatelyprovide or assist in providing the outward tension for the simulatedpelvic floor.

In various embodiments, the simulated bladder 44 is adhered to thesimulated pelvic floor 31 at the pubis, and the simulated prostate 43 isadhered to the simulated endopelvic fascia sheet 41, anterior to thesimulated rectum 53. The simulated seminal vesicles 45 are adhered onlyto the simulated prostate 43 and the simulated bladder 44. In variousembodiments, the simulated prostate, simulated bladder, simulatedseminal vesicles, simulated urethra and/or Toldt's/endopelvic fasciasheet are colored or otherwise distinguished from each other visually,e.g., colored, and/or tactilely, e.g., having different dimensions,thickness and/or length. In various embodiments, the simulated prostate,simulated bladder, simulated seminal vesicles and/or simulated urethraare all made of silicone.

In accordance with various embodiments, the colon/rectum assemblycomprises a simulated colon 51 attached to a simulated rectum 53. Thesimulated colon is contoured or has curves, bumps or other surfacefeatures thereby distinguishing the simulated colon from thesubstantially smooth and tubular simulated rectum. The transition fromthe bumpy colon to the smooth rectum forms the recto-sigmoid junction, avisual landmark during surgery and provided in various embodiments ofthe surgical simulator. In various embodiments, a simulated parietalperitoneum 54 has a proximal end or portion attached to the simulatedcolon 51 and a distal end or portion attached to the simulated rectum53. Additionally, the simulated parietal peritoneum 54 is attached tothe Toldt's/endopelvic fascia sheet with portions of themesentery/mesorectum assembly 55 disposed therebetween.

In various embodiments, a sheet of the same material used to create thesimulated Toldt's/endopelvic fascia sheet 41 is cut and attached toitself and forms the simulated mesentery 57. In various embodiments, asimulated inferior mesenteric artery (IMA) 52 is attached to thesimulated colon 51, e.g., at the proximal portion of the simulated colonand thus is only accessible and/or visible at the proximal portion ofthe TME surgical simulator.

In various embodiments, the mesentery/mesorectum assembly comprises asimulated mesentery 57 and a simulated mesorectum 58 and a simulated IMA52 and inferior mesenteric vein (IMV) 56 is attached to the simulatedmesentery 57. The simulated mesentery is attached to or integrated intothe simulated parietal peritoneum 54 where the two interfaces. Invarious embodiments, the simulated mesentery 57 and simulated mesorectum58 are a single monolithic structure with the simulated mesentery 57being at the proximal portion of the TME surgical simulator and thesimulated mesorectum 58 being at the distal portion of the TME surgicalsimulator. In various embodiments, a simulated IMA 52, IMV 56 andmesentery 57 are positioned at or in the proximal portion of the TMEsurgical simulator and thus is only accessible and/or visible at theproximal portion of the TME surgical simulator. In various embodiments,the simulated IMA and/or IMV are all made of silicone.

In accordance with various embodiments of the present invention, thefirst step of a simulated TME procedure using a laparoscopic approach isentry through the simulated parietal peritoneum. The root of themesentery is a common point of entry and can be recognized by a colordifference between the mesenteric fat and posterior abdominal wall. Thisentry point can also be recognized by observing movement in theanatomical layers when the sigmoid colon is moved with laparoscopicinstruments, as well as by the identification of the bulge of theinferior mesenteric artery (IMA) through the mesentery and peritoneum.The identification of this anatomical feature can provide a necessarystarting point for a TME procedure. Referring to the TME surgicalsimulator, the simulated parietal peritoneum 54 is adhered or otherwiseattached to the simulated visceral peritoneum more securely than thesimulated mesentery 57 to simulate realistic tenting and dissection. Thesimulated colon 51 in various embodiments is tubular and/or made ofsilicone. The simulated colon is adhered or otherwise attached on top ofthe simulated parietal peritoneum to simulate the descending colon. Invarious embodiments, the sheet thickness is increased or decreased andmay be made with a lower or higher durometer material to change theelasticity and structure of the simulated mesentery. The simulatedmesentery 57 in various embodiments is molded out of a conductivematerial to enable the user to use laparoscopic energy equipment to makeincisions. The simulated mesentery is assembled such that it is adheredto the simulated Toldt's/endopelvic fascia layer 41 up to the simulatedpelvic brim. As such, this allows abdominal dissection to bedifferentiated from the lower pelvic dissection that is performed fromthe laparoscopic approach to mobilize the rectum.

Once through the simulated parietal peritoneum 54, the surgeon candissect through the simulated avascular plane, e.g., the simulatedToldt's/endopelvic fascia layer 41, to find the simulated IMA 52, IMV56, aorta 33 and/or ureters 42. Ureter identification can be importantto avoid surgical complications and further reinforce training and theeffects of the simulation. Once the simulated structures are identified,the simulated IMA 52 can be skeletonized, ligated and divided close tothe simulated aorta. In various embodiments, these simulated organand/vascular structures, e.g., the simulated IMA, IMV, aorta and/orureter, can be cut, stapled, sutured and tied to simulate ligation anddivision. The simulated ureters and aorta allow for the identificationof the simulated IMA 52 and IMV 56 during the simulated TME procedure.In various embodiments, the simulated vasculature varies in thicknessand can be hollow or hollow and fluid filled to simulate bleeding. Oneor more of the simulated vasculatures may also disposed within thesurgical simulator without adhesion or minimal attachment, e.g.,loosely, directly adhered or otherwise attached to a silicone structureand/or any combination thereof. Dissection is continued laterally towardthe simulated abdominal sidewall mobilizing the simulated mesentery.

In various embodiments, the simulated avascular plane, e.g., thesimulated Toldt's/endopelvic fascia layer, comprises a fibrous battinglayer made of polyester fiberfill (polyfil). The tactile feedback of thefibrous layer, e.g., fibers within the batting, provides sufficientresistance to allow blunt dissection using laparoscopic instruments tobe utilized. This dissection within the fibers allows the simulatedvasculature within the layer to be skeletonized. Below or adjacent tothe simulated Toldt's fascia is a thin layer relative to the simulatedToldt's fascia that represents the layer entering the retroperitoneum orvisceral peritoneum. The thinness of or fragility of this layer(retroperitoneum/visceral peritoneum) and by extension the simulatedToldt's/endopelvic fascia layer 41 simulates the ease in which thisplane can accidently be entered, which is a challenge encountered duringthe surgical procedure and provided or simulated by the TME surgicalsimulator. In various embodiments, the simulated Toldt's fascia is afibrous layer or filling, e.g., batting, representing or simulatingconnective tissue and is disposed next to and/or attached to thesimulated retroperitoneum or visceral peritoneum, e.g., one or moresilicone sheets. The simulated Toldt's fascia and/or the simulatedretroperitoneum or visceral peritoneum are disposed next to and/orattached to the simulated parietal peritoneum 54.

In various embodiments, the simulated Toldt's/endopelvic fascia layer 41is a composite layer 41, for example, having fibrous material andsilicone, including the simulated Toldt's fascia layer along with thesimulated visceral peritoneum or retroperitoneum layer with thesimulated endopelvic fascia layer being a continuation of the combinedsimulated Toldt's fascia layer and the simulated visceral peritoneum orretroperitoneum layer. As such, together, in various embodiments, thesimulated Toldt's fascia layer and the simulated retroperitoneum orvisceral peritoneum layer form a composite layer, e.g., fibrous materialand silicone, and the simulated endopelvic fascia layer is an extensionof this composite layer, being a continuation of the combined simulatedToldt's fascia layer and the simulated retroperitoneum or visceralperitoneum layer. In various embodiments, the simulated Toldt's fascialayer and simulated visceral peritoneum or retroperitoneum layer aredisposed in the simulated abdominal cavity, and thus so named, while thesimulated endopelvic fascia layer is disposed in the simulated pelviccavity and thus so named differently. As such, reference to thesimulated endopelvic fascia layer may be used interchangeabilitythroughout the description with the simulated Toldt's/endopelvic fascialayer and vice versa. Similarly, the combined or composite layer of thesimulated Toldt's fascia and simulated retroperitoneum or visceralperitoneum may be used interchangeability throughout the descriptionwith the simulated endopelvic fascia layer and simulatedToldt's/endopelvic fascia layer and vice versa.

In various embodiments, the retroperitoneum layer or portions thereof isyellow or otherwise discernible via color or the like to furtherdistinguish or highlight the retroperitoneum layer. Within the simulatedretroperitoneum layer, there are additional fibers or fibrous material,e.g., a batting layer (simulated Toldt's fascia), that contains thesimulated aorta, nerves, and gonadal vessels. The simulated ureters andnerves are adhered or otherwise attached to the simulatedretroperitoneum 41 while the simulated aorta 33 and gonadal vessels 32are adhered or otherwise attached to the simulated pelvic floor. Invarious embodiments, the simulated pelvic floor 31 is a thin sheetmolded out of pink or blood/flesh colored silicone. The simulated nerves34, ureters 42 and gonadal vessels 32, in accordance with variousembodiments, are adhered or otherwise attached to the respectivesimulated sheets or layers at an angle, slant or similar orientationssuch that the simulated vasculature pairs are closer to each other atthe proximal end than at the distal end of the respective simulatedsheets or layers. As such, in the simulated lower pelvic region, whenthe simulated ureters and gonadal vessels are wrapped around thesimulated mesorectum 58, the simulated vasculature meet at the locationof the simulated bladder 44 and prostate 43.

To further simulate the appearance of the abdominal cavity under thesimulated retroperitoneum, in various embodiments, an additional pinksilicone layer making up the simulated pelvic floor is placed under thesimulated aorta and batting layer of the simulated retroperitoneum. Thisallows the visualization of the color of the simulated abdominal cavitywhen the simulated retroperitoneum layer is encountered.

In accordance with various embodiments, the silicone and fibrous layersthat make up the simulated mesentery, Toldt's fascia, endopelvic fascia,and/or retroperitoneum are adhered using silicone. Silicone adhesive oralternative adhesives such as cyanoacrylate adhesives and rubber cementin various embodiments are used to adhere the layers together. Whenusing silicone layers, the silicone can be readily masked within thesilicone layer and application quantities can be easily controlled withsyringes and sponge like materials, such as polyurethane foam. It alsocreates a strong silicone to silicone bond while also adhering to thefibrous layers, if any is present. The silicone to silicone bondsbetween the silicone mesentery and the fibrous material and between thefibrous material and the silicone retroperitoneum layer allow thedissection to be contained within the fibrous material, e.g., thebatting layer. Similarly, in various embodiments, silicone to siliconebonds between the silicone retroperitoneum layer and the fibrous layerand between the fibrous layer and a red silicone layer allow thedissection to be contained within the fibrous material, e.g., thebatting fibrous layer.

In accordance with various embodiments, to simulate the difference indissection within the simulated Toldt's/endopelvic fascia layer 41, theamount of adhesive, silicone, and/or pressure are used and varied.Additionally, various durometers of silicone are used to change the wayin which two parts made of silicone adhere together and tear or pullapart. This simulates different techniques of blunt dissection useful indifferent areas of the anatomy. Within the Toldt's/endopelvic fasciasheet 41, in accordance with various embodiments, more adhesive is usedrelative to the simulated retroperitoneum layer. As such, this providestactile feedback of the more difficult dissection within the correctplane, the Toldt's/endopelvic fascia sheet, versus the easier, looserdissection of the wrong plane, into the retroperitoneum. It should benoted that staying within the correct dissection layer between theToldt's/endopelvic fascia layer 41 and the mesentery/mesorectum layer57, 58 avoids surgical complications, as the dissection within simulatedretroperitoneum layer and pelvic floor 31 leads to simulated anatomicalstructures, within the simulated lower pelvis, that can be damagedduring the simulated surgical procedure.

In accordance with various embodiments, the fibers or fibrous materialattached or incorporated into the layers, e.g., withinToldt's/endopelvic fascia layer 41 and/or the retroperitoneum sheet, caninclude other low tear strength materials. These materials can be oralso include but are not limited to gel like materials and softconductive materials on which electrosurgical energy can be used. Usingfibrous materials, such as batting and the like, also enhances thesimulation providing a visual appearance of the fibers, which isobserved in the simulated surgical procedure.

In various other embodiments, the fibrous or fiber like material is notincluded or otherwise integrated into the various simulated layers orsheets, thus creating direct contact between sheets or layers ofmaterial within the surgical simulator. In such embodiments, distinctionbetween the various layers is indicated by color versus varying texturesand materials. These various embodiments or combinations thereof howevercan create added difficulty to the simulated procedure performed in thesimulated TME surgical simulator due to unrealistic visual feedback.

In accordance with various embodiments, the molding or forming ofsilicone sheets including fibrous material, e.g., batting, to extendamong or from or appear between the simulated tissue layers creates aplane of dissection in which a user must remain while completingsimulated dissection down the simulated pelvis similar to fully simulatedissection. This further allows for an enhanced and/or realistic marginfor error. Additionally, in various embodiments, the fibrous siliconecomposite material provides similar tactile and visual feedback duringthe simulated procedure and can be manipulated during manufacturing tochange the level of difficulty of the simulated procedure.

In accordance with various embodiments, simulated dissection ofToldt's/endopelvic fascia layer 41 is continued medial to lateraltowards the left sidewall of the frame in order to mobilize thesimulated left, descending colon and sigmoid colon so that the simulateddissection within the simulated lower pelvis can occur. The descendingand sigmoid colon are then freed from the sidewall of the frame bydividing the white line of Toldt. In accordance with variousembodiments, the adhesion line along the left sidewall resembles thewhite line created by the junction of two tissue planes.

Once the simulated descending colon and sigmoid colon are mobilized,posterior dissection into the simulated pelvis continues. Within thesurgical simulator, in various embodiments, the simulated sigmoid colonpasses through the silicone layer that covers the frame simulating thepubis. At the pelvic brim, a specific aspect of the TME procedure isthat the surgeon remains in the correct dissection plane between thesimulated colon/mesorectum and the simulated Toldt's/endopelvic fascialayer 41, an area between two tissue planes known as the holy plane 71.During this simulated posterior dissection, the surgeon can recognizelandmarks, such as simulated nerves 34, to ensure they are on the rightpath of dissection.

Since it is the same set of layers in the surgical simulator thatcomprise the circumferential dissection layers around the mesorectum andcolon at the posterior end, the same adhesion properties between thelayers apply. As such, dissection through the holy plane is moredifficult or notable when compared to the dissection through the wrongplane. Furthermore, in various embodiments, adjusting the amount offibrous material can make the simulated procedure more challenging. Invarious embodiments, the added fibrous material or batting strengthensthe thin silicone sheets it is added to and eases manufacturing whenadhering the simulated layers together. The simulated Toldt's/endopelvicfascia layer 41 continues posteriorly within the TME surgical simulatorto make up the outer boundary of the holy plane. Circumferentialdissection around the simulated mesorectum and colon is simulatedthrough the dissection of the fibrous material simulating the holyplane. At the posterior side of the colon 51, within the retroperitonealspace is a pair of silicone molded thin branched structures to simulatenerves, a landmark for the TME procedure. In various embodiments, thesimulated nerves 34 are colored, e.g., white, in order to be visualizedthrough the thin yellow silicone layer of the simulated retroperitoneum.The placement of the nerves within this simulated retroperitoneal spacereflects the anatomical placement of the nerves. Dissection within theretroperitoneal space within the surgical simulator would allow thesimulated nerves 34 to be encountered in this plane, which would beindicative of the dissection in the wrong plane.

In accordance with various embodiments, in the TME surgical simulator,the Toldt's fascia/retroperitoneum layer and the endopelvic fascia layerare all integrated and/or one in the same. In accordance with variousembodiments, in the TME surgical simulator, three main simulated tissueplanes or layers are provided, the simulated mesentery/mesorectum layer,the Toldt's fascia/endopelvic fascia/retroperitoneum layer and thepelvic floor/sidewall/peritoneum layer. These tissue planes should notbe confused with the two major planes of dissection, the holy plane 71,which occurs between mesentery/mesorectum 57, 58 and Toldt's/visceralperitoneum/endopelvic fascia layer 41 (“Toldt's/endopelvic fascia”) andthe wrong plane 73, which occurs between Toldt's/visceralperitoneum/endopelvic fascia (“Toldt's/endopelvic fascia”) and thepelvic sidewall layers.

Dissection into the wrong plane can cause complications, such as issueswith the presacral veins or penetration of the mesorectal enveloperesulting in an incomplete mesorectal dissection. By providingrecognizable landmarks, such as nerves, bladder, prostate and seminalvesicles, the surgical simulator ensures or assists the surgeon or userto not dissect into the wrong plane. In accordance with variousembodiments, within the simulated TME surgical simulator, the simulatednerves 34 are positioned on the posterior side of the mesorectum andcolon and dissection within the plane containing the nerves isindicative of dissection within the wrong plane. Additionally, invarious embodiments, the looser tactile feedback of and easierdissection through the simulated layers is a second indicator ofdissection within the wrong plane. Continuation of the dissection withinthis plane to the anterior side of the colon, towards the simulatedpubis will lead to simulated structures of the prostate 43, seminalvesicles 45, and bladder 44. The simulated prostate 43 and seminalvesicles 45 in various embodiments are cast using silicone or urethanefoam and colored, e.g., pigmented blue and white, respectively, toenhance the simulation or correspond with the anatomical structures theyrepresent. A simulated bladder 44, in various embodiments, is made ofsilicone and the simulated seminal vesicles are placed on either side ofthe simulated bladder. In various embodiments, the simulated prostatecomprises a silicone molded simulated urethra 46 resting underneath orextending there through. These simulated structures in variousembodiments are disposed within the frame such that they reflect theiranatomical position relative to the simulation.

In various embodiments, adhesives such as silicone adhesives orcyanoacrylate adhesives can be used to adhere the simulated componentstogether. Additionally, in various embodiments, gel, rubber, foam, andurethane materials can be used in the simulated components. In variousembodiments, silicone, silicone foams, and urethane foams have desirablematerial properties to simulate the visual appearance and tactile feel,shape, and structure of the simulated components. The simulatedanatomical structures, in accordance to various embodiments, duringassembly, are adhered on top of the layer that make up theretroperitoneum at the posterior end and are surrounded on either sideas well on top by fibrous material, e.g., batting, that makes up theretroperitoneal layer on the posterior end. Entrance into this wrongplane within the surgical simulator would be the result of dissectionthrough the thin yellow layer that makes up the retroperitoneum on theposterior end.

In various embodiments, specific or particular adhesion or otherwiseattachment patterns are used along the simulated mesentery and simulatedorgan structures to ensure relevant simulated anatomical interfaces areprovided. Variations to the way in which anterior dissection can besimulated, in accordance with various embodiments, includes the usage ofsilicone, foam and/or fibrous material to create thicker or thinnerplanes of dissection to decrease and/or increase the level of difficultyof the simulated procedure respectively. Furthermore, assembly of thesematerials can vary in relative distance from other simulated planes andlayers to provide a varying working space during the simulated TMEprocedure. In accordance with various embodiments, the TME surgicalsimulator creates a challenging surgical environment in which room forerror is provided, encouraging the development of manual dexterity andthe anatomical and surgical knowledge required to successfully performand assess the performance of the simulated TME procedure. Moreover,strategic placement of attachment points or areas creates visual andtactile feedback during a simulated anterior dissection.

In accordance with various embodiments, simulated tissue structures canbe molded out of conductive materials, which utilize visual indicatorssuch as color as opposed to utilizing visual indicators of texture.Thus, dissection in the wrong plane can be identified by changes ofcolor upon entrance into the various simulated tissue layers. In variousembodiments, the simulated dissection in the wrong plane involvesincorporation of structural supports in the surgical simulator's frameto widen the lateral sides of the colon/rectum assembly. This canfurther simulate the easier dissection encountered in the wrong plane ofdissection, and can also serve as providing additional simulatedinsufflation, i.e., providing the surgeon with a larger simulatedsurgical work space. These structural supports in various embodimentsare made of hard plastics or soft materials such as silicone, whichcreate strong adhesion points with other simulated tissue structures.

The TME surgical simulator in accordance with various embodimentsprovides adequate visual and tactile feedback to the surgeon during thesimulated procedure. Moreover, the TME surgical simulator can be alteredto adjust the difficulty of simulated dissection provided by thesimulator. To meet clinical needs, the level of difficulty of thesimulated TME procedure can be adjusted, for example, by increasing ordecreasing the amounts of fibrous tissue, adhesive and/or siliconematerial.

Simulated dissection from the laparoscopic approach is performed tocreate a circumferential dissection around the mesorectum. Thisdissection is performed within the holy plane to free the fattymesorectal envelope from surrounding structures. Circumferentialmobilization of the mesorectum is continued to the pelvic floor wherethe rectum is divided at its distal end. Due to the curve of the sacrum,visualization of the dissection from the laparoscopic end is limited;therefore, a transanal approach can be used to create thecircumferential dissection around the mesorectum. The dissection fromthe transanal end and laparoscopic end can allow for the completemobilization of the colon. The colon is then transected proximallybefore the specimen is removed. After removal, the specimen is evaluatedfor tears in the mesorectal envelope and for any exposure of the rectalwall. A complete dissection will exhibit a smooth surface with theentire outer envelope and contained volume of filling of the mesorectumintact.

In various embodiments, the simulated mesorectum structure is made ofsoft silicone and gel like materials. The posterior side 64 of a balloonor envelope formed from the simulated mesorectum structure is largerthan the anterior side 63 and/or both the proximal and distal end taper,with a more obvious taper at the distal end. The simulated mesorectumstructure, in various embodiments, includes an outer membrane, making upthe balloon, with the balloon or envelope simulating the fascia propriasurrounding a fatty envelope. This membrane in various embodiments is athin, fragile balloon layer and is made up of a silicone and fibrousmaterial composite to allow additional silicone layers to be adheredcircumferentially using silicone as adhesive. The mesorectum fatty fillin various embodiments is gel-like, soft and/or fluid enough that it canpartially escape or exit from the outer membrane upon a puncture or cutand yet still have the ability to maintain its shape within thesimulated mesorectum balloon envelope in such a way that it simulatesthe anatomical mesorectum once it has been punctured. Furthermore, thesimulated specimen is fragile enough to be accidentally breached bylaparoscopic scissors, graspers, or dissectors during the simulateddivision of the distal end of the colon and mesorectum for removal ofthe specimen. In various embodiments, due to the consistency and/oramount of the fatty fill filling the simulated mesorectum/mesentery, theexcised simulated mesorectum specimen will have visual voids or lumpsindicative of where materials have leaked out. The fibrous materialcreates structure within the gel material such that it prevents anunrealistic ejection of the gel from any given puncture site. Therefore,the simulated specimen can be graded and assessed. Grading of asimulated specimen can be assigned on a 1-3 scale where 3 is a completedissection, where the simulated mesorectum is intact without anypunctures and/or tears, 2 is an incomplete dissection with minimal tearsand/or punctures and 1 is an incomplete dissection with punctures, tearsand exposure of the rectal wall.

In various embodiments, the simulated mesorectum structure is filledwith a fatty fill 61, such as soft or dense foam, silicone, conductivematerials, gelatin and various gels such as Kraton. The simulatedspecimen may have the thin outer membrane, or the outer membrane may bemade of a gel, conductive material, or foam or if the simulatedmesorectal structure has the strength to hold its shape, the simulatedspecimen may have no outer layer.

In various embodiments, the simulated mesorectum may not simulate tissueproperties but rather is graded by color patterns and markings made onthe simulated specimen during the simulated dissection. Such embodimentscan include a molded component, which resembles the shape of themesorectum made of foam, silicone or another soft material in a color.This molded component can be tightly wrapped or coated with a siliconesheet in a contrasting color. In various embodiments, if the simulatedspecimen is punctured during simulated dissection, exposure of thecomponent color can indicate a tear or puncture.

The simulated mesorectum in accordance with various embodiments providesthe user when performing the simulated TME procedure, realistic tactileand visual feedback along with an ability to assess their surgicaltechnique. Furthermore, the simulated mesorectum can be graded uponremoval similarly to that of a specimen removed from a patient.Furthermore, the simulated mesorectum in various embodiments is madewith an outer silicone sheet, which enables adhesion to the othersilicone and fibrous components within the TME surgical simulator.

According to various embodiments, anterior dissection of the mesorectumis simulated by creating various planes made of thin silicone sheets andfibrous material, e.g., batting. The simulated mesorectum and simulatedmesentery 57, 58 are a continuous structure and are distinguished fromthe surrounding tissue by color and texture. The sheets that make up theenvelope of the mesorectum and mesentery in various embodiments aresimilar in color to the surrounding tissue. In accordance with variousembodiments, the mesentery and mesorectum are filled with a fatty fill61, e.g., a yellow gel substance that simulates fat. The presence ofthis yellow gel behind the silicone envelope that forms the outerboundary of the mesentery and mesorectum gives these structures theircolor. Simulated dissection in the correct planes is identified bysimulated anatomical landmarks such as the bladder, seminal vesicles,prostate and ureter. These simulated organ structures in variousembodiments are made of silicone and foam materials. The simulatedmesorectum 58, mesentery 57, bladder 44 and ureters 42 are assembled insuch a way that allows the surgeon to identify these useful landmarks inorder to complete the simulated TME procedure. In various embodiments,circumferential dissection of the mesorectum within the correct plane ofdissection, the holy plane, is simulated by creating a cylinder made ofa thin silicone sheet and batting composite. This thin silicone sheethas been previously described as the simulated retroperitoneum in whicha thin layer of fibrous material, such as batting, has been adhered toit to simulate the holy plane of dissection. In various embodiments, thesimulated mesorectum and the thin sheet of silicone creating thesimulated retroperitoneum, which is named the wrong plane in the lowerpelvis, are distinguished by color and texture as well as the simulatedholy plane, which lies in between and divides into two, indicating thecorrect path of simulated dissection circumferentially around thesimulated mesorectum. Location of landmarks such as nerves, ureters, andgonadal vessels, are useful for this dissection aspect the simulated TMEprocedure and are identified as being below the retroperitoneum. Theinclusion of simulated nerves 34 and ureters 42 adhered or otherwiseattached to the posterior of the simulated Toldt's/endopelvic fascialayer 41 allow surgeons to confirm they are dissecting in the correctplane.

The simulated Toldt's/endopelvic fascia layer 41 forms a tissue planearound the mesorectum 58 and in various embodiments with strategicplacement of adhesive, silicone and/or other similar attachments ensuresproper visualization of relevant simulated landmarks. In variousembodiments, variations to the way in which circumferential dissectionis simulated includes the usage of more or less silicone, foam orbatting material to create thicker or thinner planes to decrease orincrease the level of difficulty of the simulated procedurerespectively. The addition of adhesive, more silicone adhesion and/orsimilar types of attachments of the simulated Toldt's/endopelvic fascialayer 41 to the simulated mesorectum 58 can also be used to create amore challenging circumferential dissection through the holy plane. Invarious embodiments, the difficulty of dissection in the holy and wrongplanes of dissection can also be adjusted by altering the amount ofpressure used to glue the planes together. Additionally, the difficultyof dissection in the holy and wrong planes of dissection can be adjustedby changing the size of the tissue planes relative to the next outerplane. For example, by making the overall surface size of theToldt's/visceral peritoneum/endopelvic fascia (“Toldt's/endopelvicfascia”) layer smaller relative to the pelvic floor layer, thedissection through the wrong plane of dissection that exists betweenToldt's/endopelvic fascia and pelvic sidewall becomes easier, becausethere is more outward stretch or tension in the Toldt's/endopelvicfascia layer, and thus more force pulling that layer inward as the userdissects into the pelvis.

By varying the amount and/or type of fibrous material and/or attachment,e.g., silicone adhesive, pressure or the like, and/or any combinationthereof, the difficulty of dissection in the holy and/or wrong plane canbe controlled and/or varied. It should be noted however that suchadjustments or variations may distract or alter the tactile and/orvisual feedback of the surgical simulator. As such, a balancing offibrous material and/or attachments can be required or adjusted toappropriately provide the desired dissection difficulties or challengesand visual/tactile feedback. It should also be noted that the depictedholy and/or wrong planes are exaggerated in size, shape, uniformityand/or openness, to ease depiction and readability of the description.Fibrous material, adhesive and the like, for example, would extend orotherwise occupy all or portions of the dissection planes. Thedissection planes become pronounced or otherwise separated duringsimulated dissection of the surgical simulator.

In various embodiments, use of a conductive material for the simulatedmesorectum 58 and Toldt's/endopelvic fascia layer 41 can allow for theuse of energy during this segment of the simulated TME procedure.Furthermore, assembly of these materials could vary in a way such thatthe relative distance from other simulated planes and tissues willprovide a larger or tighter workspace during the simulated TMEprocedure. Furthermore, the outward tension that results from stretchingand attachment of the various layer or assemblies simulates the effectsof insufflation on dissection in the pelvic cavity. Due to insufflationbeing used in the real procedure, when the surgeon performscircumferential dissection around the mesorectum within the pelviccavity, the pressure from the insufflation gas tends to pull the tissueplanes apart as the surgeon makes cuts and bluntly dissects within thedissection plane.

Additionally, in this surgical simulator the adhesion of the siliconesimulated mesorectum to the simulated silicone visceral peritoneum layervia the batting layer provides room for puncturing and tearing of thesimulated mesorectum that cannot be achieved with usage of varyingmaterials that do not adhere to silicone.

In various embodiments, there is a pronounced shape of the simulatedmesorectum 58 where it is curved and more voluminous on the posteriorside following the curve of the sacrum while remaining thinner on theanterior side towards the pubis. In various embodiments, the transanalapproach for the simulated TME procedure can be used to mobilize therectum and mesorectum in the low pelvis region. In this approach, thesurgeon uses a transanal access system, platform and/or channel toaccess the rectum, create a purse string and occlude the rectum. Acircumferential incision is made around the purse string to gain entryinto the holy plane. Entry into the holy plane from the transanalapproach requires a great deal of skill and anatomical knowledge. Invarious embodiments, a simulated transanal adapter is used to gain entryinto the simulated rectum. The transanal adapter allows for the surgicalsimulator the interface to a simulated laparoscopic trainer. The adaptercontains a rigid component that locks into the top and bottom torso ofthe trainer. The rigid component can be made of urethane or plastic.Molded into the adapter is a soft silicone layer that contains a smallopening that simulates the anus in which the access platform caninterface with. Variations in materials to simulate the anus and flesharound the adapter can include soft rubber like materials or rigidmaterials. The use of the soft materials allows the flexibility andability to manipulate access instruments within the simulated orifice.In various embodiments, the use of silicone allows a strong silicone tosilicone bond to be used when interfacing with additional siliconecomponents found within the simulated TME surgical simulator.

In accordance with various embodiments, at the distal end of thesimulated TME surgical simulator, the simulated rectum 53 extends beyondthe frame such that it can be placed around the access channel that ispenetrated through the orifice of the adapter described above. Thediameter of the rectum, in various embodiments, is smaller than theaccess channel to allow the rectum to be stretched around the channeland remain secure. In various embodiments, the simulated rectum can bedirectly adhered or otherwise directly attached to the silicone portionof the adapter. As such, the access channel would be inserted throughboth the adapter and colon simultaneously, which could be challengingfor a user due to the difference in size that allows the tight interfacefit. The extension of the rectum at the distal end beyond the frame ofthe surgical simulator and beyond the circumferential dissection layersprovide sufficient length for the access channel to remain in place. Invarious embodiments, the frame and/or the dissection layers can extendto be adjacent with the adapter. This in turn would cause the surgicalsimulator at the distal end to become stiffer and less mobile, which isunrealistic to the anatomy.

Once the access channel is placed, the inner lumen of the simulatedcolon is encountered, and the laparoscopic instruments can be used tocreate a purse string. In various embodiments, mesh can be embeddedwithin the simulated rectum 53 to increase or enhance its tear strengthenough to withstand forces generated by suturing. In variousembodiments, additional material is used to simulate the rectum,enhancing its strength to hold a suture without the use of mesh and/orin combination with the mesh. The additional materials can includesilicone, Kraton, other rubber like materials, and/or combinationsthereof. Once a purse string is created, the inner lumen of thesimulated colon is occluded, exposing the circumferential dissectionlayers around the rectum.

In accordance with various embodiments, at the distal (anal) end, therectum is followed by the mesorectum fatty fill 61, which is encasedwithin a silicone envelope, and the outermost layer of the mesorectalsilicone balloon or envelope is adhered or otherwise attached to theToldt's/endopelvic fascia sheet or layer. The plane of dissectionbetween the envelope of the mesorectum and endopelvic fascia representsthe holy plane. The simulated endopelvic fascia sheet 41, in variousembodiments, is a thin yellow layer that is called the retroperitoneumin the pelvic cavity during the simulated laparoscopic approach. Betweenthe endopelvic fascia and pelvic sidewall is another layer of fibrousmaterial, which creates or represents the wrong plane of dissection.Around this fibrous layer is a pink silicone layer to visually representthe pelvic floor/pelvic sidewall. The layers are adhered or otherwiseattached together, such that upon placement of the purse string, thesimulated rectum and mesorectum cinch in such a way that access to thecorrect (holy) and incorrect (wrong) planes 71, 73 for simulateddissection are allowed. These planes of dissection occur between themesorectum and endopelvic fascia and between the endopelvic fascia andpelvic sidewall. During simulated circumferential dissection of thesimulated mesorectum from the transanal entry, the wrong plane 73 caneasily be entered due to the cinching of a culmination of the surgicalsimulator's simulated planar tissue layers at the distal end of themesorectum. This creates a confined work environment thereby simulatingthat, which could be found in a patient. The wrong plane may be enteredfrom the transanal approach and entry into the wrong plane can bevisualized by color and texture change, as well as the tactile feedbackbetween the ease of the dissection between the planes. The holy planehas a more difficult and/or tactile response in comparison to thedissection through the wrong plane. In various embodiments, this hapticfeedback response is simulated through the variation in adhesion orattachments between the fibrous layers extending into or between theplanes.

In accordance with various embodiments, entry via the transanal approachmay vary in the shape of the simulated pelvis structure, which can bealtered to create a smaller or larger work environment and/or changingthe proximity of the simulated tissue layers, and landmarks can alsoalter the level of difficulty of the simulated TME procedure. In variousembodiments, simulated entry via the transanal approach may furtherinvolve incorporation of additional structural supports in the frame toenable improved tissue structure interface and simulated insufflation,providing the surgeon a greater amount of simulated surgical workspace.These structural supports, in various embodiments, may be made of hardplastics or soft materials such as silicone, which create strongadhesion points with other simulated tissue structures, made ofsilicone. The simulated transanal entry of the TME surgical simulator inaccordance with various embodiments provides adequate challenge incompletion of the simulated TME procedure by creating a confined workenvironment that resembles the confined space found within a pelviccavity, and allows room for entrance into the wrong plane, which is alearning objective for a TME procedure. Moreover, the simulated rectum53 holds the purse string long enough for the surgeon to occlude therectum and enter the holy plane. In various embodiments, the simulatedmesorectum at the transanal end of the TME surgical simulator is taperedto resemble or simulate the taper of the mesorectum in a patient. Invarious embodiments, the simulated mesorectum 58 does not have a taperat the transanal end but resembles or simulates the bulge of themesorectum as found in a patient. In a similar variation, the mesorectumcan encapsulate the rectum at the same thickness from end to end of thefatty envelope. In various embodiments, the taper at the transanal endof the mesorectum allows access into the holy plane within the tightworkspace of the transanal end of the surgical simulator, while alsoproviding the ability for the user to enter the wrong plane if they aretoo aggressive in their dissection.

The narrow pelvis in male patients can pose a challenge for surgeons toreach the pelvic floor from a laparoscopic approach after completecircumferential dissection of the mesorectum. As such, in variousembodiments, the TME surgical simulator provides a simulated pelvisstructure, e.g., the frame/housing 20, 20′, that supports the simulatedtissue structures and creates a confined work environment, whichsimulates the natural curves of the pelvis. In various embodiments, asshown in FIGS. 18-20, the frame 20′ comprises plastic sheets 29 cut,folded and assembled and in various embodiments in such a way that theyresemble the deep sacrum curve of the pelvis. This curve creates limitedvisualization during dissection, thus provides another simulated featurein the TME surgical simulator. The plastic sheets, in variousembodiments, are interfaced with thick silicone sheets through aperturesin the frame sheets. These silicone sheets do not serve as anatomicalfeatures, but rather are used to secure simulated tissue structures,e.g., silicone tissue components, to the plastic frame components. Invarious embodiments, silicone is used to adhere the silicone tissuestructures to the silicone sheets interfaced with the frame componentsforming durable silicone bonds that enhance or strengthen the TMEsurgical simulator. Similarly, simulated tissue structures, in variousembodiments, are also adhered or otherwise attached to domed fixtures 28that are then fastened or otherwise attached to the frame providingtension for the simulated tissue structures. Outward extension, stretchand/or tension, e.g., circumferential tension, of the simulated tissuecan further simulate insufflation provided during laparoscopicprocedures.

During surgery, insufflation gas stretches out the tissue planes withinthe patient. Thus, when the surgeon makes cuts in the tissue, thetension created by the insufflation gas makes the tissue planes pullaway from each other. This is especially evident as the surgeon movesfrom the abdominal cavity to the pelvic cavity. This is also part of thereason why it is so easy to enter the wrong plane of dissection, and tocontinue in the wrong plane as dissection is continued into the pelvis.As such, in various embodiments, simulated tissue structures within theTME surgical simulator, especially within the pelvic cavity, are placedunder circumferential tension as a way to simulate the behavior oftissue planes that are under tension as a result of insufflation.

In various embodiments, the frame is made of thin plastic sheets thatadds flexibility and enables formation of the curvature of the simulatedpelvis without the need of additional bends, cuts, sheets and fasteners.Additionally, in various embodiments, the silicone sheets used forassembly may be adhered to the frame with adhesive and/or fasteners. Inaccordance with various embodiments, the frame provides a confined andchallenging work environment including limited visibility duringposterior dissection through the holy plane. Moreover, in variousembodiments, the frame creates supports that can be utilized to providesimulated insufflation to the surgical simulator as well as manipulatethe level of difficulty of the surgical simulator by widening ornarrowing the work environment. In various embodiments, the modularityof having the frame be assembled by at least two pieces or componentsfacilitates the assembly of the TME surgical simulator.

In various embodiments, the TME surgical simulator final assembly beginswith the colon/rectum/mesentery/mesorectum assembly, which is the mostinterior assembly in the TME surgical simulator. Toldt's/endopelvicfascia assembly is attached around the mesorectum/rectum assembly, thenthe prostate assembly is added, and then the pelvic floor is attachedto/around the toldt's/visceral peritoneum/endopelvic fascia. After thesoft layers have been adhered or otherwise attached in place around themesorectum, plastic/silicone components that interface the softsubassembly to the frame are attached in place to the final softsubassembly. The silicone subassembly is such that its outer surface isslightly smaller than the inner surface created when then plastic framecomponents are finally assembled. This size mismatch between the layersin the silicone subassembly and plastic frame results in circumferentialtension of all tissue layers within the pelvic cavity of the surgicalsimulator. In various embodiments, this circumferential tension is thefeature of the surgical simulator that provides simulated insufflationfurther enhancing the realism of the simulation.

In accordance with various embodiments, the TME surgical simulatorassembly begins with a fully assembled frame 20′ or a single monolithicframe 20. The pelvic floor/sidewall assembly adhered or otherwiseattached into the frame. The Toldt's/visceral peritoneum/endopelvicfascia (“Toldt's/endopelvic fascia”) layer is adhered or otherwiseattached to the pelvic floor/sidewall and themesorectum/mesentery/colon/rectum assembly is adhered or otherwiseattached within the Toldt's/endopelvic fascia layer 41. When attached insuch a fashion, each successive layer is under outward tension. Thisoutward tension causes the layers or subassemblies to pull away fromeach other when dissection occurs between the layers, which create arealistic simulation of what occurs in a patient during laparoscopicdissection due to tension created by the insufflation gas.

In accordance with various embodiments, outward circumferential tensionis achieved when the frame is formed with the simulated assemblies,e.g., the simulated mesorectum 58 or endopelvic fascia layers 41,already adhered to one another, with portions of the frame attached tothe outermost layer of the simulated assemblies. The frame being largerthan the simulated assemblies or layers causes the simulated layers tostretch as the frame is assembled or formed. This stretching that occursduring frame assembly provides this outward tension on the attachedsimulated tissue assemblies. This outward tension simulates insufflationwithout the use of insufflation gases or a sealed enclosure.

As a result of this pre-created or initially created outward tension, asthe simulated dissection occurs, the corresponding simulated assembliesor layers tend to separate simulating the effects of insufflation. Forexample, during the simulated dissection, the outer layer or layersbeing attached to the frame remains fixed or tends to move outward oraway from the inner layer or layers due to the release of the weight ofthe inner layer, the retraction or tendency of the material to movetowards the frame and/or combination thereof. The inner layer, beingseparated from the outer layer, is released from the outward tension andthus moves or tends to move inward or away from the outer layer. Theweight of the inner layer, the retraction or tendency of the material toreturn to a non-tension or pre-stretch state and/or a combinationthereof can further cause the inner layer to move away from the outerlayer.

In various embodiments, the pre-created outward tension is formed aseach simulated assembly or layer is formed. For example, each simulatedassembly is subjected to outward tension as it is attached to the frameor the preceding simulated layer between it and the frame. As such, eachsimulated assembly is pre-stretched and then attached to the precedingsimulated layer or frame. Thus, tension is added to the simulatedassembly or layers as these layers are added to the surgical simulator,resulting in the layers being less stiff, destructive when separatedand/or overly adhered or attached to the other simulated layers orframe. In this method, glue and pressure are applied to the layers whilethey are pre-stretched, although glue and pressure quantities can becontrolled independently of the layer size, and all characteristics,along with batting quantity, must be in balance to achieve the desireddissection qualities.

In various embodiments, the fibrous material can be thicker or thinnerto affect dissection and overall tactile feel of the surgical simulator.The simulated assembly, e.g., the endopelvic fascia layer, includes wetsilicone layers, one or more layers providing a waterproof barrier andone or more layers providing a bond with the fibrous material, and canalso be made thicker. Making the silicone layer or layers thicker canmake simulated dissection easier, as it becomes more difficult to damageor mishandle the simulated assembly with surgical instruments.Additionally, making the silicone thicker can increase the outwardtension compared to a thinner layer of the same size and shape.

In reference to FIGS. 11A-11B, a before stretching/tension configurationis depicted in FIG. 11A and an after configuration is depicted in FIG.11B, to illustrate an exemplary configuration in which the simulatedendopelvic fascia 41 is not or minimally stretched or otherwisetensioned and the simulated mesorectum 58 is stretched considerably orotherwise tensioned relative to the simulated endopelvic fascia 41 inaccordance with various embodiments of the present invention. In such aconfiguration, dissection in the holy plane 71 is easier than in thewrong plane 73 as the simulated mesorectum 58 tends to separate from thesimulated endopelvic layer 41, as the mesorectum tends to return to itspre-stretched or non-stretched form. Easier holy plane dissection isless challenging or less difficult for a training surgeon as they willmore likely dissect in the “correct” holy plane instead of the wrongplane.

In reference to FIGS. 12A-12B, a before stretching/tension configurationis depicted in FIG. 12A and an after configuration is depicted in FIG.12B, to illustrate an exemplary configuration in which the simulatedmesorectum is not or minimally stretched or otherwise tensioned and thesimulated endopelvic fascia 41 is stretched considerably or otherwisetensioned relative to the simulated mesorectum 58. In such aconfiguration, dissection in the wrong plane 73 is easier than in theholy plane 71 as the simulated mesorectum 58 would not tend to separatefrom the simulated endopelvic layer 41, the mesorectum having no orminimal tendency to bias to move inward or away from the endopelvicfascia layer 41. On the other hand, the simulated endopelvic layer wouldtend to separate from the simulated pelvic floor or towards thesimulated mesorectum 58, as the simulated endopelvic layer 41 will tendto return to its pre-stretched or non-stretched form. Easier wrong planedissection is more challenging or more difficult for a training surgeonas they may dissect in the wrong plane instead of the “correct” holyplane.

In reference to FIG. 13, a neutral or no/minimal stretching/tensionconfiguration is depicted to illustrate an exemplary configuration inwhich the size of the simulated mesorectum and endopelvic fascia layers58, 41 match the size of the frame and layer thickness of previoussimulated layers so that they are adhered or otherwise attached in placewithout being placed under outward tension, stretching or the like. Inthis situation, in accordance with various embodiments, the difficultyof dissection is controlled or adjusted only by the fibrous material,pressure, adhesive/attachments and/or combinations thereof, as thelayers are not subjected to outward tension and thus would not tend orbe pre-conditioned to separate from each other. In various embodiments,as shown, for example, in FIG. 8B, the simulated endopelvic fascia andmesorectum layers 41, 58 are stretched or otherwise tensioned so thatthere is a simulated insufflation effect within both the holy and wrongplanes 71, 73. In various embodiments, as such, the simulated endopelvicfascia layer 41 is stretched or otherwise tensioned more than thesimulated mesorectum 58 so that the wrong plane dissection is slightlyeasier, but the simulated mesorectum is still stretched as well.

In various embodiments, the mesorectum fatty fill 61, e.g., a pre-madenon-liquid fatty fill, is injected or otherwise introduced into themesorectum/mesentery as one of the final steps. As a result, the fattyfill does not negatively affect the process of adhering or otherwiseattaching the simulated tissue layers together and, in particular, theattachment between the mesorectum and endopelvic fascia can be enhancedto accurately simulate the holy plane of dissection between these twolayers. Furthermore, in various embodiments, the outer layer of themesorectum can be made very thin and fragile, e.g., made of a thin andfragile sheet of silicone, which enhances the realism of the TMEsurgical simulator and its ability to be used for assessment purposes.

In various embodiments, the simulated fatty fill comprises sodiumpolyacrylate, opaque agar gel, water and/or any combination thereof. Itshould be noted that gelatin and agar gels can be used for mesorectumfatty fill. However, gelatin melts at a low temperature (e.g., about35°) thereby limiting its usefulness and agar gel exhibits syneresiswhen the gel is broken, which causes an unrealistic leaking of waterfrom the mesorectum when the mesorectum is damaged.

It should be noted that various drawings are provided in asemi-schematic fashion to ease identifying and description of the TMEsurgical simulator. As such, the TME surgical simulator provided hereinmay intentionally not be made so uniform in places and/or the spacingbetween simulated structures as the drawings may suggest.

In various embodiments, a surgical simulator comprises a simulatedparietal peritoneum layer, a simulated mesorectum and mesentery layerconnected to the simulated parietal peritoneum layer and togetherforming a envelope there between. In various embodiments, the surgicalsimulator further comprises a simulated fatty fill disposed within theenvelope. In various embodiments, the simulated fatty fill comprisessodium polyacrylate, agar gel, and/or a gel. In various embodiments, thesimulated mesorectum and mesentery layer is puncturable and/or made of athin puncturable silicone sheet.

In various embodiments, a surgical simulator comprises a frame having aproximal portion defining a simulated abdominal cavity and a distalportion defining a simulated pelvic cavity. In various embodiments, asimulated endopelvic fascia layer is disposed within the simulatedpelvic cavity, a simulated pelvic floor layer is attached to thesimulated endopelvic fascia layer and the distal portion of the frame.In various embodiments, a simulated mesorectum layer is attached to thesimulated endopelvic fascia layer. In various embodiments, the simulatedmesorectum layer and the simulated endopelvic fascia layer define asimulated dissection plane therebetween.

In various embodiments, the simulated endopelvic fascia layer, thesimulated pelvic floor layer, the simulated mesorectum layer and/or anycombination thereof are placed under circumferential tension, stretched,pre-stretched and/or pre-tensioned. In various embodiments, thesimulated endopelvic fascia layer is larger than the simulated pelvicfloor layer. In various embodiments, the simulated endopelvic fascialayer is thicker and/or longer than the simulated pelvic floor layer.

In various embodiments, a surgical simulator comprises a frame having aproximal portion defining a simulated abdominal cavity and a distalportion defining a simulated pelvic cavity. In various embodiments, asimulated visceral peritoneum layer is disposed within the simulatedabdominal cavity. In various embodiments, a simulated parietalperitoneum attached to the simulated visceral peritoneum layer and theproximal portion of the frame. In various embodiments, a simulatedmesentery layer is attached to the simulated visceral peritoneum layer.In various embodiments, the simulated mesentery layer and the simulatedvisceral peritoneum layer define a simulated dissection planetherebetween.

In various embodiments, a surgical simulator comprises a simulatedendopelvic fascia layer and a simulated mesorectum layer with at leastone of the simulated endopelvic fascia layer and a simulated mesorectumlayer are placed under circumferential tension, stretched, pre-stretchedand/or pre-tensioned. In various embodiments, a surgical simulatorcomprises a simulated mesorectum layer and a simulated parietalperitoneum layer connected to each other and forming there between anenvelope and a simulated fatty fill is disposed within the envelope. Invarious embodiments, a surgical simulator comprises a simulatedendopelvic fascia layer and a simulated mesorectum layer, the simulatedendopelvic fascia layer is attached to the simulated mesorectum layer todefine a simulated dissection plane there between. In variousembodiments, a surgical simulator comprises a simulated visceralperitoneum layer and a simulated mesentery layer, the simulated visceralperitoneum layer is attached to the simulated mesentery layer to definea simulated dissection plane there between. In various embodiments, asurgical simulator comprises a simulated pelvic floor layer and asimulated mesorectum layer, the simulated pelvic floor layer is attachedto the simulated mesorectum layer to define a simulated dissection planethere between. In various embodiments, a surgical simulator comprises asimulated pelvic layer and a simulated mesentery layer, the simulatedpelvic floor layer is attached to the simulated mesentery layer todefine a simulated dissection plane there between. In variousembodiments, a surgical simulator comprises a first composite siliconesheet connected to a second composite silicone sheet. In variousembodiments, at least one of the first or second composite siliconesheets are placed under circumferential tension, stretched,pre-stretched and/or pre-tensioned. In various embodiments, a surgicalsimulator comprises a silicone sheet connected to a composite siliconesheet to define a simulated dissection plane there between. In variousembodiments, a surgical simulator comprises a first composite siliconesheet connected to a second composite silicone sheet to define asimulated dissection plane there between. In various embodiments, asurgical simulator comprises a silicone sheet connected to a compositesilicone sheet to form an envelope therebetween and a simulated fattyfill is disposed within the envelope. In various embodiments, a surgicalsimulator comprising a silicone envelope and a gel comprising at leastone of sodium polyacrylate and opaque agar. In various embodiments, thesimulated fascia layer is the simulated endopelvic fascia layer, thesimulated Toldt's fascia/visceral peritoneum layer, the simulatedToldt's fascia, the Toldt's/endopelvic fascia layer and/or anycombination thereof. In various embodiments, the surgical simulator doesnot include a frame or base and/or in various embodiments includes oneor more simulated structures, components and the like without a frame orthe like.

The above description is provided to enable any person skilled in theart to make and use the present invention and perform the methodsdescribed herein and sets forth the best modes contemplated by theinventors of carrying out their inventions. Various modifications,however, will remain apparent to those skilled in the art. It iscontemplated that these modifications are within the scope of thepresent disclosure. Different embodiments or aspects of such embodimentsmay be shown in various figures and described throughout thespecification. However, it should be noted that although shown ordescribed separately each embodiment and aspects thereof may be combinedwith one or more of the other embodiments and aspects thereof unlessexpressly stated otherwise. It is merely for easing readability of thespecification that each combination is not expressly set forth.

Although the present invention has been described in certain specificaspects, many additional modifications and variations would be apparentto those skilled in the art. It is therefore to be understood that thepresent invention may be practiced otherwise than specificallydescribed, including various changes in the size, shape and materials,without departing from the scope and spirit of the present invention.Thus, embodiments of the present invention should be considered in allrespects as illustrative and not restrictive.

The invention claimed is:
 1. A surgical simulator for simulating a totalmesorectal excision procedure, comprising: a frame having a proximal endand a distal end; a simulated tissue layer connected to and covering anopening of the proximal end of the frame, wherein the simulated tissuelayer comprises a simulated parietal peritoneum and a simulatedmesentery connected under the simulated parietal peritoneum, and whereinthe simulated parietal peritoneum and the simulated mesentery define anenvelope therebetween; and a simulated rectum extending through aportion of the distal end of the frame, wherein the envelopecircumferences at least a portion of the simulated rectum, wherein theenvelope comprises conductive material that is configured to be cutusing electrosurgical energy, and wherein at least a portion of theenvelope and the simulated rectum is configured to be removed as part ofa simulation for a total mesorectal excision procedure.
 2. The surgicalsimulator of claim 1 further comprising a simulated colon disposed ontop of the simulated parietal peritoneum and attached to the simulatedrectum.
 3. The surgical simulator of claim 1 further comprising asimulated fatty fill disposed within the envelope, wherein the simulatedfatty fill is configured to resemble fat thereby not retaining anyparticular shape or a shape defined by the envelope.
 4. The surgicalsimulator of claim 1, wherein the frame comprises a floor and a roofwith at least one sidewall connecting the floor to the roof.
 5. Thesurgical simulator of claim 4 further comprising a simulated pelvicfloor connected to the frame floor.
 6. The surgical simulator of claim 5wherein the simulated pelvic floor is connected to the frame roof. 7.The surgical simulator of claim 6 further comprising a simulated aortaconnected to the simulated pelvic floor.
 8. The surgical simulator ofclaim 6 further comprising simulated nerves connected to the simulatedpelvic floor.
 9. The surgical simulator of claim 8 further comprising asimulated bladder disposed under the frame roof.
 10. The surgicalsimulator of claim 9 further comprising a simulated prostate disposedunder the frame roof.
 11. The surgical simulator of claim 10 furthercomprising a simulated urethra disposed under the frame roof.
 12. Thesurgical simulator of claim 5 further comprising a simulated fascialayer disposed between the simulated pelvic floor and the simulatedparietal peritoneum, the simulated fascia layer being made of fibrousmaterial and the simulated parietal peritoneum being made of silicone.13. The surgical simulator of claim 12 further comprising simulatedureters attached to the simulated fascia layer.
 14. The surgicalsimulator of claim 5 further comprising simulated Gonadal vesselsconnected to the simulated pelvic floor.
 15. The surgical simulator ofclaim 1, wherein a portion of the frame associated with the proximal endis larger than a portion of the frame associated with the distal end,and wherein the portion of the frame associated with the proximal end isset higher or above the distal end of the frame.
 16. The surgicalsimulator of claim 1, wherein a first amount of adhesive is used inconnecting a first portion of the envelope and the simulated rectumcompared to a second amount of adhesive used to connect a second portionof the envelope and the simulated rectum to provide different tactilefeedback in connection with the removal of the envelope, wherein agreater amount of adhesive is configured for a more difficult dissectionin a correct plane, and a lesser amount of adhesive is configured for aneasier dissection in a wrong plane.
 17. The surgical simulator of claim1, wherein the envelope comprises a plurality of silicone layers andfibrous layers between the silicone layers, and wherein the fibrouslayers are configured to be dissectible thereby directing wheredissection should occur.
 18. The surgical simulator of claim 17, whereinportions of the envelope comprise different types of materialsconfigured to provide different tear strength thereby indicating whethertearing of the envelope at a specific location is appropriate or not,wherein the envelope incorporates low tear strength materials includinggel like materials and soft conductive materials within the plurality ofsilicone layers to facilitate dissection of the layers.
 19. The surgicalsimulator of claim 17, wherein the fibrous layers are configured toprevent unrealistic ejection of the fatty fill when the envelope ispunctured.
 20. The surgical simulator of claim 1, wherein the simulatedrectum further comprises a lumen that is configured to be viewable afterthe removal of the portion of the envelope and the simulated rectum, thelumen providing features that facilitate a grading of a performance ofthe total mesorectal excision procedure simulation.
 21. The surgicalsimulator of claim 1, wherein the simulated rectum further compriseshigh tear strength material including mesh that facilitates thesimulated rectum to withstand forces generated during suturing.
 22. Asurgical simulator comprising: a simulated parietal peritoneum layer; asimulated mesorectum and mesentery layer connected to the simulatedparietal peritoneum layer and together forming an envelope therebetween; a simulated rectum having a rectal lumen; and a simulated fattyfill, configured to resemble fat, disposed within the envelope, whereinthe envelope and at least a portion of the simulated rectum isconfigured to be removed to simulate a total mesorectal excisionprocedure, wherein the simulated fatty fill comprises a gel-likesubstance configured to not retain any particular shape or a shapedefined by the envelope, and wherein the simulated fatty fill isconfigured to partially leak, escape, or exit from the envelope when theenvelope is punctured or cut, wherein the envelope further comprises afibrous material configured to prevent unrealistic ejection of thesimulated fatty fill when the envelope is punctured, and wherein theenvelope and the rectal lumen are configured to facilitate a grading ofa user performance simulating the total mesorectal excision procedure.23. A surgical simulator for surgical training comprising: a framehaving a single monolithic structure with proximal end and a distal end,the frame comprising a proximal enlarged open area extending from theproximal end of the frame and connected to a distal enclosure with adistal opening at the distal end of the frame, the frame furthercomprising: a frame floor extending from the proximal end of the frameto the distal end of the frame, the frame floor at a proximal portion ofthe frame being disposed higher than the frame floor a distal portion ofthe frame; a frame roof spaced from the frame floor and disposed onlyabove the distal portion of the frame floor; and sidewalls connectingthe frame floor to the frame roof with the frame floor, the frame roofand the sidewalls defining the distal enclosure; a simulated pelvicfloor connected to and covering an upper surface of the frame floor andconnected to and covering a lower surface of the frame roof, thesimulated pelvic floor being made of a material different from the framefloor and the frame roof; a simulated rectum extending through thedistal opening of the distal enclosure, the simulated rectum having adistal end extending past the distal end of the frame; a simulated colonhaving a proximal end extending past the proximal end of the framehaving a distal end connected to a proximal end of the simulated rectum,the simulated colon having contours and the simulated rectum beingsmooth; a simulated prostate positioned entirely within the distalenclosure of the frame and disposed between the simulated rectum and theframe roof; simulated Gonadal vessels connected to a proximal portion ofthe simulated pelvic floor and disposed between the simulated colon andthe frame floor at the proximal portion of the frame, the simulatedGonadal vessels being visible at and accessible via the proximal end ofthe frame; a simulated parietal peritoneum connected to the simulatedcolon; a simulated mesentery disposed between a proximal portion of thesimulated parietal peritoneum and the proximal portion of the simulatedpelvis floor; a simulated mesorectum encompassing the simulated rectum,the simulated mesentery and the simulated mesorectum being formed as asingle monolithic structure, wherein the simulated mesentery, thesimulated mesorectum and the simulated parietal peritoneum define anenvelope therebetween; a simulated fatty fill disposed within theenvelope, the envelope being made of silicone and the simulated fattyfill being made of sodium polyacrylate and opaque agar; wherein theenvelope has a proximal portion and a distal portion, the distal portionof the envelope being larger than the proximal portion of the envelopeand an amount of simulated fatty fill in the distal portion of theenvelope being greater than an amount of simulated fatty fill in thedistal portion of the envelope; and wherein the simulated rectum extendsinto and through the distal portion envelope with the simulated fattyfill surrounding portions of the simulated rectum and a simulatedinferior mesenteric vein is disposed within the proximal portion of theenvelope.
 24. The surgical simulator of claim 23, wherein the simulatedmesorectum is pre-stretched, having an outward tension away from aninterior of the frame and the simulated rectum and further comprising asimulated endopelvic fascia minimally stretched and attached to thesimulated pelvic floor, the simulated endopelvic fascia having anoutward tension away from the interior of the frame and the simulatedmesorectum less than the outward tension of the simulated mesorectumaway from the interior of the frame and the simulated rectum.
 25. Thesurgical simulator of claim 23, wherein the simulated mesorectum isminimally stretched, having an outward tension away from an interior ofthe frame and the simulated rectum and further comprising a simulatedendopelvic fascia pre-stretched and attached to the simulated pelvicfloor, the simulated endopelvic fascia having an outward tension awayfrom the interior of the frame and the simulated mesorectum greater thanthe outward tension of the simulated mesorectum away from the interiorof the frame and the simulated rectum.